Polyethylene glycol (PEG) has been used for over 30 years to increase the serum half-life of protein drugs. Despite its wide use, the mechanism of conformational stabilization for PEG has remained elusive. In this work we present a model for PEG based conformational stabilization based on noncovalent interactions. We have sown that PEG can increase the stability of salt bridges, hydrogen bonds and nonpolar interactions. We aim to use PEG to exploit noncovalent interactions to be able to predict PEG-based stabilization.